A processing apparatus may include a plasma source coupled to a plasma chamber to generate a plasma in the plasma chamber, an extraction plate having an aperture disposed along a side of the plasma chamber; a deflection electrode disposed proximate the aperture and configured to define a pair of plasma menisci when the plasma is present in the plasma chamber; and a deflection electrode power supply to apply a bias voltage to the deflection electrode with respect to the plasma, wherein a first bias voltage applied to the deflection electrode is configured to generate a first angle of incidence for ions extracted through the aperture from the plasma, and a second bias voltage applied to the deflection electrode is configured to generate a second angle of incidence of ions extracted through the aperture from the plasma, the second angle of incidence being different from the first angle of incidence.